springboot 调用http的post接口

在Spring Boot中，可以使用Java内置库或第三方库来调用HTTP的POST接口。

1. 使用Java内置库

可以使用Java内置库中的HttpURLConnection类来发送POST请求。示例代码如下：

import java.net.HttpURLConnection;
import java.net.URL;
import java.io.OutputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class HttpPostExample {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://example.com/api/post");
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setDoOutput(true);
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type", "application/json");

            String data = "{\"message\":\"Hello, World!\"}";
            OutputStream os = conn.getOutputStream();
            os.write(data.getBytes());
            os.flush();

            BufferedReader br = new BufferedReader(new InputStreamReader((conn.getInputStream())));
            String output;
            while ((output = br.readLine()) != null) {
                System.out.println(output);
            }

            conn.disconnect();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

2. 使用第三方库

可以使用第三方库如Apache HttpComponents或OkHttp来发送POST请求。示例代码如下：

使用Apache HttpComponents:

import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

public class HttpPostExample {
    public static void main(String[] args) {
        try {
            HttpClient httpClient = HttpClientBuilder.create().build();
            HttpPost request = new HttpPost("http://example.com/api/post");

            StringEntity params = new StringEntity("{\"message\":\"Hello, World!\"}");
            request.addHeader("content-type", "application/json");
            request.setEntity(params);

            HttpResponse response = httpClient.execute(request);
            String responseBody = EntityUtils.toString(response.getEntity());

            System.out.println(responseBody);

        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

使用OkHttp:

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

public class HttpPostExample {
    public static void main(String[] args) {
        try {
            OkHttpClient client = new OkHttpClient();
            RequestBody body = RequestBody.create("{\"message\":\"Hello, World!\"}", MediaType.parse("application/json"));
            Request request = new Request.Builder()
                    .url("http://example.com/api/post")
                    .post(body)
                    .build();

            Response response = client.newCall(request).execute();
            String responseBody = response.body().string();

            System.out.println(responseBody);

        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

以上是使用Java内置库和第三方库调用HTTP的POST接口的示例代码，你可以根据自己的需要选择其中一种方式来实现。